Oxide Glass-Based Phosphors for White Light Emitting Diodes: Current Status, Challenges, and Future Perspective

Glass-based phosphors are widely studied materials for white light-emitting diodes (WLEDs) due to their tunable structural, thermal, and optical properties. The amorphous glass network allows uniform dispersion of activator and sensitizer ions, offering broad compositional flexibility and efficient control over emission wavelength, quantum yield, and color purity. Various oxide and fluoride glass systems including silicate, borate, phosphate, and oxyfluoride provide distinct phonon energies and structural environments that directly influence radiative and nonradiative processes and hence the performance of the phosphor. Embedding phosphor particles into low-melting glass matrices enhances heat dissipation, refractive-index matching, and long-term reliability, making phosphor in glass (PiG) structures suitable for high-brightness and high-temperature LED operation. This review provides a comprehensive overview of the fundamental photoluminescence (PL) properties of glass-based phosphors, including their energy-transfer pathways, host-matrix selection criteria, and quenching mechanisms that influence overall performance. It also examines major fabrication approaches, such as melt-quenching, sol-gel, chemical vapor deposition (CVD), physical vapor deposition (PVD), and advanced crystallization methods. Finally, the review highlights current challenges and outlines future opportunities for enhancing glass-based phosphors, with the goal of achieving higher luminous efficacy, improved color rendering, and stable white-light emission.